Firearm hammer



Oct. 6, 1970 E. s. VARTANIAN ETAL 3,531,386

FIREARM HAMMER Filed May 29, 1968 2 Sheets-Sheet 1 INVENTORS EDWIN S.VARTA/V/AN JAY P JARVIS ATTORNEY 0d. 6, 1970 E. YARTANIAN ETAL 3,531,886

' FIREARM HAMMER Filed May 29, 1968 2 Sheets-Sheet 2 l g 4 E ii f Z v jI, v H IrZ/ J INVENTORS saw/1v s. VAR TAN/AN JAY R JARVIS ATTORNEYPatented Oct. 6, 1970 3,531,886 FIREARM HAMMER Edwin S. Vartanian, NorthHaven, and Jay P. Jarvis,

West North Branford, Conn., assignors t Olin Mathieson ChemicalCorporation, a corporation of Virginia Filed May 29, 1968, Ser. No.732,989 Int. Cl. F41c 11/02, 19/00 US. Cl. 42-69 4 Claims ABSTRACT OFTHE DISCLOSURE A two-piece firearm hammer having a tough metal bodymember and a; hard sear-engaging element connected thereto.

When forming a hammer for use in a firearm, it is desirable to form thebody or striking portion of the hammer from a tough steel so as tomaximize the resistance of the hammer to shearing forces directedtherethrough each time the hammer strikes a firing pin or cartridge.When mounted in a firearm, a portion of the hammer engages a searingmember when the hammer is in a cocked position, the searing memberserving to releasably latch the hammer in the cocked position. Thesearing member is operatively connected to a trigger which is operableto disengage the sear from the hammer, thus releasing the latter tostrike the firing pin or cartridge. In order to provide for superioroperation of the trigger assembly, that portion of the hammer whichengages the sear must have a very smooth finish. The smooth finish isrequired to prevent chattering from occurring between the hammer and thesear as the latter is moved across the sear-engaging portion of thehammer and out of engagement therewith. Chattering between the sear andhammer is undesirable because it makes the shooter consciously aware ofthe movement of the trigger as the latter is squeezed, and distracts theshooter from focusing his attention on aiming the gun. Not only must thesear-engaging portion of the hammer be originally provided with a verysmooth surface, but the surface must also be resistant to nicking andwearing that will occur as a result of repeated contact between the searand the sear-engaging portion of the hammer. While toughness is adesirable characteristic of a firearm hammer from the standpoint ofresisting impact stress, a tough metal will not necessarily provide theneeded resistance to nicking and wear which is essential to thesear-engaging portion of the hammer. In order to provide such wearresistance, the sear-engaging portion of the hammer must becomparatively hard. In order to obtain the desired hardness on thesear-engaging portion of the hammer, the latter must be subjected to aheat treatment, which heat treatment undesirably lowers the toughness ofthe remainder of the hammer. Thus the conventional one-piece hammer ofthe prior art cannot attain the optimum toughness and hardness withoutexpensive and time-consuming differential heat treatment.

In order to overcome the above problems and to provide a firearm hammerhaving a body portion of superior toughness, and a sear-engaging portionof superior hardness and smooth finish, a hammer is formed in accordancewith this invention having two distinct connected members. The main bodyis formed from a steel, steel alloy, or other metal which is heattreated to maximize its toughness, and the sear-engaging portion is adistinct member or element formed of a steel, steel alloy, or othermetal which is heat treated to maximize its hardness. After heattreating the sear-engaging element is provided with a smooth finish andis attached to the main body of the hammer.

It is, therefore, an object of this invention to provide a firearmhammer having superior trigger pull characteristics.

It is a further object of this invention to provide a firearm hammerformed from a pair of distinct bodies connected together.

It is yet another object of this invention to provide a firearm hammerhaving a body member of superior toughness, and a sear-engaging memberof superior hardness and smooth finish, which sear-engaging member isconnected to the body member.

Other features, objects and advantages of this invention will becomeapparent to one skilled in the art from an examination of the succeedingspecification and accompanying drawings, in which:

FIG. 1 is an exploded view of a firearm hammer partially in sectionformed in accordance with this invention;

FIG. 2 is a perspective view of the assembled hammer of FIG. 1 showingthe position of the sear-engaging element on the hammer body:

FIG. 3 is a side view of a cut away portion of a firearm incorporatingthe hammer of FIG. 2, wherein the hammer is shown in its cocked positionin engagement with a scar; and

FIG. 4 is a side view similar to FIG. 3 but showing the hammer in itsfired position after disengagement from the sear.

Referring now to FIG. 1, a preferred embodiment of the hammer of thisinvention is shown. The hammer includes a main body member 2 having ahead portion 4 adapted to strike a firing pin or cartridge; and anintegral foot portion 6 manually positioned in a firearm adjacent a searmember. A recess 8 is formed in the foot portion 6 and a laterallyextending hole 10 is disposed in the member 2 so that the latter may bepivotally mounted in a firearm. The body member 2 is preferably formedfrom a medium carbon steel, having a carbon content of from about.40.50%, such as 1050 steel or 4140 steel alloy. The hardness of themember 2 is, for example, in the range of 404-5 on the Rockwell C scale,and the toughness of the member 2 as measured by the Izod impact testis, for example, in the range of 20-35 ft. lbs.

The hammer further includes a sear-engaging element in the form of a pin12 having a barrel portion 14 and a head portion 16. The barrel portion14 is frictionally fitted into the recess 8 in the hammer foot 6, withthe head portion 16 protruding from the hammer foot 6, as is clearlyshown in FIG. 2. The head portion 16 in cludes a working surface 18which engages a sear memher (see FIG. 3). The pin 12 is preferablyformed from a high carbon steel, such as, for example, 1095 steel, whichhas been heat treated to a hardness in the range of, for example, 60*65on the Rockwell C scale. The working surface 18 has a surface finish ofno more than 16 micro inches, with the preferable finish being in therange of 48 micro inches. The finish on the working surface 18 may beeconomically and efiiciently provided by a centerless grinding operationdue to the cylindrical shape of the pin 12. It is noted that the extremehardness of the pin 12 permits and preserves the smooth finish on theworking surface 18. While the head portion 16 is shown as beingcylindrical in shape, it is to be understood that the head of the pincan be formed in any of a variety of cross-sections, such as,rectangular, triangular, or the like, without departing from the spiritof the invention. To be operable, the head portion of the pin needmerely be capabled of being provided with a smoothly finished workingsurface.

It is further noted that experimentation has shown that were the hammerbody heat treated to a hardness of 60- 65 on the Rockwell C scale, theIzod impact value would decrease to about 6 ft. lb., and thus thetoughness of the hammer would be substantially lowered.

FIG. 2 is a perspective view of the hammer of FIG. 1, showing the pinhead 16 protruding from the hammer foot 6 so as to expose the workingsurface 18 for engagement with a sear means.

FIG. 3 shows the hammer 2 mounted in a firearm 20 (only partially shown)for operation with a simple trigger system. The trigger system includesa trigger 22 which is pivotally mounted on a pin 24 and which includesan integral sear means 26. A spring 28 is connected to the sear 26 andthe firearm 20 to bias the trigger 22 and sear 26 in a counter-clockwisedirection about the pin 24. The hammer 2 is pivotally mounted on a pin30 and a hammer spring 32 is connected to the pin 30 to bear against thehammer 2 and bias the latter in a clockwise direction about the pin 30.A bolt member 34 is partially shown with a firing pin 36 extending fromthe rear face thereof, the bolt 34 being shown in its battery position.The hammer 2 is shown in its cocked position in FIG. 3, with the sear 26engaging the working surface 18 of the protruding head 16 on thesear-engaging element 12.

FIG. 4 shows the hammer 2 after the trigger 22 has been pulled torelease the sear 26 from engagement with the sear-engaging element 12.As the trigger 22 is pulled to the left, the trigger system pivots aboutthe pin 24 against the bias of the spring 28 and the right hand edge ofthe sear 26 slides across the working surface 18 until the sear 26clears the head 16. At this point, the hammer 2 pivots about the pin 30under the influence of the hammer spring 32 and the hammer head 4strikes the firing pin 36.

While the hammer of this invention is shown in operation with a verysimple trigger assembly, it is readily apparent that this hammer can beused with trigger assemblies of substantially greater complexity.

It will be readily appreciated by those skilled in the art that thisinvention provides a firearm hammer having requisite toughness anddisplaying superior trigger pull characteristics. The hammer of thisinvention provides for the preservation of the superior trigger pullcharacteristics even after repeated use, by having a smoothly finishedsear-engaging surface of substantially higher hardness than theremainder of the hammer. The provision of a distinct sear-engagingelement which is afiixed to the hammer permits formatiton of the formerwith an accuracy and quality which would be impractical were the hammerformed as a unitary piece in the conventional manner, and furtherpermits a substantially higher hardness to be imparted to the element.

What is claimed is:

1. A hammer for use in a firearm, said hammer comprising a toughmetallic member having an impacting portion; a separate metallicsear-engaging element connected to said member, said element having asmoothly finished working surface protruding from said member, saidelement being of substantially higher hardness than said member.

2. The hammer of claim 1, wherein said member includes a recess, andsaid sear-engaging element is a pin fitted into said recess.

3. The hammer of claim 1, wherein said working surface has a finish ofnot more than 16 micro inches.

4. The hammer of claim 1, wherein said member has a hardness of about4045 on the Rockwell C scale, and said element has a hardness of about6065 on the Rockwell C scale.

References Cited UNITED STATES PATENTS 10/1913 Smith 42-69 3/1960 Lewis4265

